There are better languages for making big money as a salaryman than PHP.

The arguments that PHP is still modern/relevant are more arguments for its use in getting things done. If you just want to maximize income as an employee, learn Rust, Go, or Java. (Or Swift or C# if you wanna go into Those industries and stick with dead-end fanservice languages.)

Furthermore, if you’re a senior team lead, you’re a manager, not a programmer. Why do you care which language is used at that point? UML is UML.